For getting to a soft synth's property page, I just double click in the Browser Pane, with the Synth tab clicked (Browse Synth Rack), and what I am double-clicking on there is the icon on the far left side of a given synth's entry there - the icon looks like a little round midi connector and a keyboard.
That opens up the property page for the desired synth without fail for me, and it has not changed in that for several years - at least 8.5 I believe.
Can you please tell me precisely what you are double-clicking on?
Also, I open up an inserted effect's property page by simply double-clicking on it in the effects bin for the track/bus in question.
Can you tell me there as well what precisely you are double-clicking on that it is not coming up?
Bob Bone